The presently disclosed embodiments relate generally to layers that are useful in imaging apparatus members and components, for use in electrostatographic, including digital, apparatuses. More particularly, the embodiments pertain to an improved metallization process for making fuser members, such as for example, inductively heated fuser belts.
In electrophotography, also known as xerography, electrophotographic imaging or electrostatographic imaging, the surface of an electrophotographic plate, drum, belt or the like (imaging member or photoreceptor) containing a photoconductive insulating layer on a conductive layer is first uniformly electrostatically charged. The imaging member is then exposed to a pattern of activating electromagnetic radiation, such as light. Charge generated by the photoactive pigment move under the force of the applied field. The movement of the charge through the photoreceptor selectively dissipates the charge on the illuminated areas of the photoconductive insulating layer while leaving behind an electrostatic latent image. This electrostatic latent image may then be developed to form a visible image by depositing oppositely charged particles on the surface of the photoconductive insulating layer. The resulting visible image may then be transferred from the imaging member directly or indirectly (such as by a transfer or other member) to a print substrate, such as transparency or paper. The imaging process may be repeated many times with reusable imaging members. The visible toner image thus transferred on the print substrate, which is in a loose powdered form and can be easily disturbed or destroyed, is usually fixed or fused to form permanent images. The use of thermal energy for fixing toner images onto a support member is well known. In order to fuse electroscopic toner material onto a support surface permanently by heat, it is necessary to elevate the temperature of the toner material to a point at which the constituents of the toner material coalesce and become tacky. This heating causes the toner to flow to some extent into the fibers or pores of the support member. Thereafter, as the toner material cools, solidification of the toner material causes the toner material to be firmly bonded to the support.
Several approaches to thermal fusing of electroscopic toner images have been described in the prior art. These methods include providing the application of heat and pressure substantially concurrently by various means: a roll pair maintained in pressure contact; a belt member in pressure contact with a roll; and the like. Heat may be applied by heating one or both of the rolls, plate members or belt members. The fusing of the toner particles takes place when the proper combination of heat, pressure and contact time is provided. The balancing of these parameters to bring about the fusing of the toner particles is well known in the art, and they can be adjusted to suit particular machines or process conditions.
Fuser and fixing rolls or belts may be prepared by applying one or more layers to a suitable substrate. Typically, fuser and fixing rolls or belts comprises a surface layer for good toner releasing. Cylindrical fuser and fixer rolls, for example, may be prepared by applying a silicone elastomer or fluoroelastomer to serve as a releasing layer. The coated roll is heated to cure the elastomer. Such processing is disclosed, for example, in U.S. Pat. Nos. 5,501,881; 5,512,409; and 5,729,813; the disclosure of each of which is incorporated by reference herein in their entirety. Known fuser surface coatings also include crosslinked fluoropolymers such as VITON-GF® (DuPont) used in conjunction with a release fluid, or fluororesin such as polytetrafluoroethylene (hereinafter referred to as “PTFE”), perfluoroalkylvinylether copolymer (hereinafter referred to as “PFA”) and the like.
A heating member is typically provided for thermal fusing of electroscopic toner images. Several heating methods have been described for toner fusing in the prior art. In order to shorten the warm up time, the time required heating the fuser or fixing member to the fusing temperature, induction heating technique has been applied for toner fusing. An image fusing or fixing apparatus utilizing induction heating generally comprises a fusing member such as a roll or belt, an electromagnet component comprised of, for instance, a coil, which is electrically connected to a high-frequency power supplier. The coil is arranged at a position inside the fusing member or outside and near the fusing member. The fusing member suitable for induction heating comprises a metal heating layer. When a high-frequency alternating current provided by the power supplier is passed through the coil, an eddy current is induced within the heating metal of the fusing member to generate thermal energy by resistance to heat the fusing member to the desired temperature.
For example, U.S. Pat. Nos. 7,060,349 and 7,054,589, discloses an image fixing belt suitable for induction heating and a method of manufacturing the same, which is hereby incorporated by reference.
In the context of electrophotographic fusing members, the key components include a fuser belt with a multi-layer configuration comprised of, for example, a polyimide substrate, deposited on the substrate, a metal heating layer comprised of nickel or copper, an optional elastic layer comprised of an elastomer, and an outmost releasing layer.
In a conventional manner, the metal heating layer in such fusing members is deposited on the substrate by using electroplating method. Prior to the electroplating, the surface of the non-conductive substrate, such as polyimide, must be rendered to electrically conductive through several steps, including surface pretreatment such as etching, then applying a catalyst for electroless plating using a colloidal solution comprising, for example, palladium catalyst, followed by electroless plating to form a thin conductive metal layer. A subsequent electroplating process is then applied to form a thick uniform metal layer comprised of, for example, copper and or nickel, with desired thickness. The need for catalyst seeding and electroless plating of the substrate surfaces involved with conventional electroless techniques are some of the key technical challenges for making the fusing belts in order to produce a thick metal coating. Thus, it is desired to devise a more simple and efficient manner of metallization technique for use in making fuser members, for example, fuser belts.